Introduction Flea biology Fleas
5.2.1. Rodent fleas
Much of what is known about fleas is based on the biology of rodent fleas, especially Xenopsylla spp. on domestic rodents and Oropsylla montana and other flea species on ground squirrels Metzger Rust, 2002. Rodent fleas have been the subject of intense biological investigation Gage Kosoy, 2005 because they are the vectors of the causa- tive agents of two significant human diseases, bubonic plague and murine typhus. Most rodent fleas are nest fleas, moving onto the host only to feed.5.2.2. Cat fleas
The cat flea Ctenocephalides felis is not considered a major threat to human health because, as it is rarely found on rodents, it usually has little chance to transmit disease agents from rodent reservoirs to humans. Also, it has been shown to be an inefficient vec- tor of plague Pollitzer, 1954. It does, however, produce significant discomfort, due to a pruritic reaction to salivary secretions, both in human beings and in other animals. The cat flea is a serious urban pest, infesting pets, such as dogs and cats, as well as urban wildlife, such as the northern raccoon Procyon lotor, the Virginia opossum Didelphis virginiana , the striped skunk Mephitis mephitis, foxes Vulpes spp. and coyotes Canis latrans Rust Dryden, 1997. In urban settings, these wild animals, as well as feral cats and dogs, maintain cat flea populations and build a natural reservoir for reinfestation of domestic pets. Even homes without a pet can experience severe cat flea problems, if wild or feral animals nest in the crawl space or attic and share their fleas. Typically, migrant animals den under the structure in the spring; once the young leave the nest, it is aban- doned, and the fleas left behind climb up through subflooring, avidly seeking a blood- meal from any warm-blooded host.5.2.3. Flea development
Because rodent fleas and cat fleas share many similarities in their life-cycles, the cat flea will be used to provide an overview of flea development. Differences between them are provided to distinguish the two. The eggs of cat fleas are oval, measuring 0.5 mm in length, with tiny openings called aeropyles in one end of their white shells. A female cat flea produces about one egg an hour while she remains on the host. The smooth eggs are not sticky, so they easily sift through the host’s pelage to collect in the surrounding environment, concentrating in areas where the host spends the most time. Cat flea eggs hatch in 1–10 days, depending on temperature and humidity Dryden Rust, 1994. The majority of eggs hatch within 36 hours at 70 relative humidity and 35°C, while at 13°C most of the eggs hatch within six days Silverman, Rust Reierson, 1981. Flea larvae are white, legless, eyeless maggot-like creatures, covered sparsely with hairs. A neonate is scarcely larger than the egg from which it emerged, while full-grown lar- vae are about 5 mm long. Larvae live off the host, feeding on organic debris and adult Fleas 1565.1. Introduction
While over 2200 species of fleas are known worldwide, most of them are of no public health significance and do not have an impact on people or their companion animals, because they are found only on specific wild hosts. Of primary health and veterinary concern are rodent fleas, especially Xenopsylla spp., and fleas found on companion ani- mals, Ctenocephalides spp.. While other flea species, such as L eptopsylla segnis the European mouse flea, are found on peridomestic animals, they are considered unlikely vectors Pratt Wiseman, 1962. Both Xenopsylla spp. and Ctenocephalides spp. have worldwide distribution.5.2. Flea biology
Fleas have developed two host-mainte- nance strategies. Host fleas remain on the host, exhibiting strong fidelity to the ver- tebrate, once a host is acquired, and aban- doning their vertebrate host only when it dies. The host provides food as blood, warmth and shelter, giving the flea little incentive to leave the host, especially since there is no guarantee of it acquiring ano- ther host. T he flea’s need to frequently feed increases its inclination to remain near the host Fig. 5.1. In contrast, nidi- colous fleas remain in the nest, moving to the host only to feed Krasnov, Khokhlova Shenbrot, 2004. N est fleas parasitize animals such as rodents that return to the nest daily, ensuring that the flea will be able to obtain regular blood-meals. Typically, nest fleas are poor jumpers, moving primarily by crawling, while host fleas have well-developed jumping legs. While the adult flea is dependent on the vertebrate host, flea larvae live off the host. Nevertheless, they also depend on host blood, in the form of adult flea faeces, for nutri- tion. Adult fleas ingest much more host blood than they need or can utilize for their own nutrition; thus, adult flea faeces are often described as being partially digested or undi- gested host blood Rust Dryden, 1997. Rodent and cat flea species have similar holo- metabolous life cycles, with free-living larval stages undergoing complete metamorpho- sis, resulting in the parasitic host-dependent adult stage. Fig 5.1. Adult fleas feed exclusively on blood Source: Photo by N.C. Hinkle. Public Health Significance of Urban Pests 1595.3. Health risk and exposure assessment
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» Risk of developing allergic sensitization
» Risk factors for developing asthma
» Public health impact of urban asthma
» Dust sampling Airborne sampling Comparison of various methods of allergen exposure assessment
» Cockroach sensitization and asthma
» Size characteristics of airborne mouse and rat allergens Residential exposures
» Dust mites Studies examining thresholds of exposure relevant to disease
» Cockroaches Rodents Studies examining thresholds of exposure relevant to disease
» Comprehensive avoidance of dust mite allergens Multifaceted primary prevention studies
» Limited avoidance of dust mite allergens
» Targeting housing conditions of high-risk groups
» Smokybrown cockroach American cockroach Oriental cockroach
» Brownbanded cockroach Allergy and asthma overview
» Food contamination and disease transmission
» Cost of control and management
» Impact of poverty Cockroaches
» Public costs 1. Cost of health-related conditions
» IPM of cockroaches Cockroaches
» Baits Cockroach control: pesticide applications
» Alternative strategies Cockroach control: sanitation practices
» Biological control Conclusions Cockroaches
» Origins and natural history Habitats within the home
» Food Limiting factors Distribution in Europe and N orth America
» CEH Distribution in Europe and N orth America
» The building envelope Impact of building construction
» The ventilation and heating system
» Furniture and furnishings Overall effect of the housing environment on health or illness
» Sampling methods Dust mite and allergen inspection and detection methods
» Mechanical solutions Modifying environmental conditions
» Washing Dusting Dry cleaning Vacuuming
» Home disinfectants Electric blankets Bed heaters Freezing
» Sunlight Steam cleaning Cleaning
» Autoclaving Steam cleaning Temperature control
» Barrier fabrics Temperature control
» Habitat modification Carpets Physical control methods
» Soft furnishings Air filters
» Anti-allergy sprays Antimicrobial treatments Dehumidifiers
» Pesticides Building construction Methods of house dust mite control
» Control methods Medical practitioners Other
» Background Biology and bionomics
» Other species of Cimicidae that can affect people
» Evidence of resurgence in N orth America
» Future prospects Resurgence of bedbug populations in Europe and North America
» Importance as pests Economic impact Bites and health effects
» Conducive environmental conditions An integrated approach to bedbug management
» Physical removal Exclusion Physical removal and exclusion
» Inspection Detection Inspection, detection and education
» Heat Cold Controlled atmospheres
» Use of pest management products
» Benchmarks for success in bedbug management Conclusions
» Introduction Flea biology Fleas
» Health risk and exposure assessment
» Cost for control and management
» Cost of health-related conditions
» Flea exclusion and physical removal Pesticide applications for flea control
» Foggers General surface treatments IGRs
» On-animal products Conducive environmental conditions
» Pharaoh ant biology Overview of biology and distribution in Europe and North America
» Health hazards 1. Pharaoh ant infestations: pathogen transmission and contamination
» Pharaoh ant distribution and population monitoring
» Fire ant population assessment and monitoring methods
» Fire ant geographic range and potential expansion Fire ants: stinging incidents
» Fire ants: cost of eradication
» Physical exclusion Residual contact insecticides
» Insecticidal baits Fire ants: cost of health-related issues, control and management
» Efficacy of management practices
» Implementation of fire ant control programmes
» Confirmation. Determine where control is needed.
» Fire ants Emerging problems and policy options
» Introduction Biology and bionomics of filth flies in Europe and North America
» N uisance Health hazards 1. Diseases
» Myiasis Health hazards 1. Diseases
» Pesticide applications for fly control Granular baits
» Fly exclusion practices Crack-and-crevice treatments Biological control
» Ultraviolet light traps Sticky traps Jar or bag traps Window traps
» Attractants Perimeter treatments Fly management
» Togaviridae: genus Alphavirus Viruses
» Orthomyxoviridae: genus Orthomyxovirus Bacteria
» Coxiellaceae Anaplasmataceae Spirochaetaceae Bacteria
» Regular nonsporing Gram-positive rods Mycobacteriaceae
» Microsporidia Babesiidae Eimeriidae Protozoa
» Zoonoses and sapronoses of wild birds in the urban ecosystem
» Monitoring and surveillance Management implications 1. Benchmarks
» Techniques for dispersing birds in cities
» Control of wild and feral birds in urban areas
» Economic impact of wild urban birds on human health and of controlling birds
» Introduction Human body lice
» Biological factors Implications for public health
» Louse infestation in Europe and North America
» Physical removal Pesticides Louse management 1. Inspection and detection
» Socioeconomic influences Conducive environmental conditions
» Benchmarks for lice management
» Introduction Ticks of Europe and North America
» LB in Europe and N orth America
» Geographical distribution Lyme borreliosis
» Public health impact of TBE in Europe
» Geographical distribution Geographical distribution Epizootiology and epidemiology
» HME HGA Crimean-Congo haemorrhagic fever
» Boutonneuse fever Rickettsia helvetica
» Clothing Tick removal Clothing impregnation Vaccination
» Host-centred methods Habitat manipulation and urban design
» Tick and tick-borne disease surveillance IPM
» Public activities Pesticide applications
» Surveillance and management Research
» Other mosquito-borne viral infections that cause encephalitides
» Malaria Mosquitoes as a pest nuisance
» Dengue haemorrhagic fever and yellow fever
» Dirofilariasis The spread of mosquitoes and mosquito-borne pathogens
» National reporting and Mosquitoes
» Mosquito control and management
» Sanitation and water management
» Adulticiding Larviciding Mosquito monitoring
» Use of predators biological control Passive protection
» Genetic control and transgenic mosquitoes
» Feeding Biology of commensal rodents 1. Description and natural history
» Reproduction and life cycle of commensal rodents
» Behaviour relevant to control
» Movement Biology of commensal rodents 1. Description and natural history
» Population growth and socialization of commensal rodents
» Sewers and drains Association with urban infrastructure 1. Rodents in housing
» Case study 1 – rat bites in Philadelphia: identifying the factors contributing to risk
» Zoonoses of mice Public health risks in urban areas
» Case study 2: Fairhill case study
» Tree squirrels Types, distribution and abundance
» Chipmunks Ground squirrels, antelope ground squirrels and prairie dogs
» Hamsters Voles Types, distribution and abundance
» Beavers Types, distribution and abundance
» Rabbits and hares Types, distribution and abundance
» Francisella tularensis Major rodent- and lagomorph-related bacterial and rickettsial agents
» California group viruses primarily La Crosse virus CTF virus
» Yersiniae Major rodent- and lagomorph-related bacterial and rickettsial agents
» Borrelia burgdorferi s.l. Tick-borne relapsing fever borreliae
» Toxoplasma Toxocara Major rodent- and lagomorph-related parasitic agents
» Babesiae Leptospirae Major rodent- and lagomorph-related parasitic agents
» Bartonellae Rat-bite fever agents
» Flying squirrels Ground squirrels and antelope ground squirrels
» Tree squirrels Voles and other microtine rodents
» Chipmunks Disease associations with particular types of rodents
» Beavers Disease associations with particular types of rodents
» Rabbits and hares Old World mice
» Dormice N ew World rats and mice
» Introduction The impacts of anthropogenic transformations
» Risk factors for rodent- and lagomorph-related diseases Public health impact
» Costs, control and management of infestations
» Control and management of non-commensal rodents and rodent-related diseases
» Conclusions Non-commensal rodents and lagomorphs
» EU community-level authorization of technical grade active ingredients
» Acute toxicity The precautionary principle
» The substitution doctrine Special considerations given to children’s health
» Toxicity end-points Pesticide hazard identification
» Long-term effects Pesticide hazard identification
» Insecticide synergists N eonicotinoid insecticides
» Spot applications Primary exposure of non-professional users and secondary exposures
» Inhalation Routes of exposure
» Incidental oral exposure Routes of exposure
» Exposure potential Steps of pre-market risk assessment of pesticides
» Tiered approaches to exposure estimation: a basis for risk assessment
» Mathematical mechanistic models Empirical models Some existing models
» Statistical mathematical models SOPs and exposure scenario types
» Comparing pesticide risks from residential and dietary exposures
» Residential applicator exposure assessment
» Toxicity end-points and MOS Residential applicator exposure
» Future actions and data development
» Identification Establishment of threshold levels
» Inspection Evaluation of effectiveness
» Develop an IPM plan Employment of two or more control measures
» Definitions of IPM An integrated approach to managing urban insects and rodents
» Case study 3 Case study 4 Case study 5
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